Knee joint prosthesis



FIG. 1 is a perspective view of a knee joint prosthesis showing our new design as seen from the top front;

FIG. 2 is a perspective view thereof as seen from the top rear;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof. 

The ornamental design for a knee joint prosthesis, substantially as shown and described. 